Final answer:
A. Visceral pleura
The serous membrane that directly lines the surface of the lungs is the visceral pleura. It forms the inner layer of the pleura and works along with the parietal pleura to reduce friction in the pleural cavity.
Step-by-step explanation:
The serous membrane lining the surface of the lungs is known as the visceral pleura. The pleura of the lungs consist of two main layers: the visceral pleura and the parietal pleura. The visceral pleura is the layer that directly covers the lungs, extending into and lining the lung fissures, while the parietal pleura is the outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The space between these two layers is called the pleural cavity, which is filled with a small amount of serous fluid that helps to reduce friction during lung expansion and contraction.